Manufacture of mononitrocrlorobenzene



Pstente i May 25, i926.

e we n i i? Wlmmm 50H W'. LIVINGSTOH, ST. LOUIS, MISSOURI, AND LET'S/AS P. IFZYRIDES, OF BUFHUHQG,

NET 'YGBI'K.

75o mowing.

This invention relates to an improvccl process for nitrating chlorobenzene and more particularly to the manufacture of mononitrochlorobenzene.

@ It is well-known that when chlorohenzene is nitrated by subjecting it to the action of nitretizig agents that Various mono-, diand poly-nitroderiiatives are produced (isnenriing on the character of the nitrating' 19 regents employed and on the conditions,

especially time, acid concentration and temperature, under which the process of nitrotion is carried out. Y i

It has been heretofore purposeci to efi'ect w the nitration of chlorohenzene forthe prodnction of mononitrochlorobenzene, and particularly dinitrochlorobenzene, by slowly adding chlorohenzene to a mixture of c0ncentrsterl suifuric acid, sp. gr. 1.831.84:,

93 and sodium or potassium nitrate. In proceecling in this way, it is difiicult to control the reaction so as to proriuce the desired nitration products and obtain economic yields, the tendency being either for the re- 55 action to proceed incompletely or to proceed too energetically with formation of a. mix- ,ture of products which ere contaminated with other nitro bodies or with impurities such as tors, resins, etc. Moreover, at times,

39 temperatures are reached which give rise to dangerous reactions accompanied by copious evolution of oxides of nitrogen and conse' quent loss of considerable quantities of nitric ocirl. I

According to the present invention. we

have discovered that the nitration of chlorohenzene may be efi'ectively and economically carried out by subjecting it to the ectionof a mixture of sodium nitrate, or an equiva- Q lent nitrate, encl sulfuric acid provided suit able conditions of temperature, acid concentrstion, proportions, agitation, etc, maintained. We have found that by the initial use of a weaker sulfuric said than hitherto employed, and at a higher initiai temperature, the nitration of chlorobenzene takes place readily-end is easily controlled. Under these conditions, the sulfuric acid refidiiy dissolves the sodium nitrate forming sodium acid sulfate, most of which, if

not all, remains, in solutionpwhile the addition of stronger sulfuric acid during; the nitration preserves, within limits, the concentretion oi the sulfuric acid medium #59 throughout the. course of the reaction. The

MANUFACTURE OF MOHONITBQCHLGROHENZENE.

Application filed August 8, 1925. Serial No. 49,166

substance are addedin the some period of time. The addition of the sulfuric :iciri anti. chlorohenzene may be (ione from calibrated tanks and the amounts edcierl mrav so regulated as to relatively chrresnoncl, op proximately so, to the amounts or sodium nitrste added. in this wey, there is at no time s vioient reaction, the mixture is resalily emulsifiech end regular end uniform nitrution takes place with minimum 1:? anger of local over-action.

The following specific example for the production of mononitrochlorohenzene 'Wiil further illustrate the invention, but it is uu-.

derstood that the invention is not limited thereto. The. parts are by weight. simple: A Well stirred mixture of about 1600 parts sulfuricecid of about 531% strength. and 200 parts inonochlorohenzene is heated to about in e jacketed nitration kettle equipped with an effective agitator. To the hot, agitated and emulsifier .mixture, whose temperature is controlled or regular means of cooling or heating with Water or steam in the jacket as may he require a, there is gracluuily addetl about lli'opurts pulverized commercial sodium nitrate, preiorably of 96 to 98 percentpurity anfi. 1600 parts sulfuric acid of about '93 percent strength, and 1240 parts 1nonochlorohenzene,

111 such rs manner and at such s rate that proportional parts, or' nearly so, of eech substance are arhied in ehoutthe some periocl of time. Y

Under such conditions it is not possihle for unreoeteol sodium nitrate to he at any given time in more than small amounts.

The heat of nitration soon raises the temperature to above The reaction is maintained at ahout-ll6bto C. by the rate of. addition 'oii-the components erii by the cooling and heeting inenns' available. It

the components.

ner.

usually requires about two to live hours to add After all the components have been added, the reaction mixture is further maintained at a temperature of about 110 to 180 C. for about one hour, or until the nitration is complete. hen. the nitration is completed, the nitration product which is comprised almost wholly oi the mononitrochlorobcnzene, can be isolated in any suitable and well-lrnown man- For example, the reaction mixture may be added-to water or it may be allowed to settle, the spent acid drawn oil, and the nitration product washed with water or dilute caustic alkali, orv both, and, if desired, subsequently distilled. Calculated on the chlorobenzene used, the yield of mononitrochlorobenzene is excellent.

In the above example, the invention may be carried out by mixing all of the chlorobenzene with the diluted sulfuric acid of about 81%, at the beginning of the operation and subsequently adding only the nitrate and the strong sulfuric acid in proportionate amounts. The reaction can also be carried out by adding some Inononitrochlorobenzene into the reaction kettle before the start of the nitration in which case the reaction can be carried out at temperatures ranging up to the boiling point of mononitrochlorobenzeue. It is further understood that the term strong sulphuric acid includes oleum.

The present invention makes it possible to nitrate chlorobenzene and obtain mononitrochlorobenzene in excellent yield and in a state of high purity, being almost entirely free from tars, resins, etc, as Well as from polynitro compounds by the use of solid sodium nitrate, or other nitrates and sulfuric acid. It permits the nitration to be carried out under conditions easily controlled. The rate at which the sodium nitrate and sulphuric acid are subsequently added depends on the external cooling or heating means available, thus permitting a smooth nitraticn without the evolution. of large quantities of oxides of nitrogen.

We claim as our invention 1. The process of nitrating chlorobenzene to mononitrochlorobenzcne which comprises the gradual and proportional addition of chlorobenzene and sodium nitrate to sulfuric acid having a strength of between about 65- 90 percent at a temperature between about and 240 C.

2. The process of nitrating chlorobcuzene to mononitrochlorobenZeno which comprises the gradual andproportional addition of sodium nitrate, sulfuric acid stronger than 85 percent, and chlorobcnzenc to sulfuric acid of about 65430 percent strength at a temperature of between about 70 and 240 (1 3. The process of nitrating chlorobenzene to mononitrochlorobeuzene which comprises the gradual and roportionate addition of chlorobenzene and sodium nitrate to a well agitated sulfuric acid of between about 65 and percent strength and chlorobenzene heated to a temperature of between about 70 C and the boi ing point of chlorobenzene.

4. The process of nitrating chlorobenzenc to mononitrochlorobcnzenc which comprises the gradual and proportionate addition of chlorobenzene and sodium nitrate to a well agitated mixture of sulfuric acid of between about 65 and 90 percent strength and mononitrochlorobenzene maintained at a temperature between about 70 C. and the boiling point of mononitrochlorobcuZeno.

5. The process of nitrating chlorobenzene to mononitrochlorobenzene which comprises the gradual and proportionate addition of chlorobenzene and sodium nitrate to a well agitated mixture of about 65-90 percent sulfuric acid, chlorobenzene and 1nononitrochlorobenzene maintained between about 7 0 C. and. the boiling point of mononitrochlorobenzene,

6. The process of nitrating chlorobenzene to mononitrochlorobenzene which comprises the gradual and proportionate addition 01 chlorobenzene and sodium nitrate to well agitated sulfuric acid of between about 65 and 90 percent strength at a temperature between about 70 and 130 C.

7. The process of nitrating chlorobenzene to mononitrochlorobenzene which comprises the gradual and roportionate addition of chlorobenzcne, sul 111'i0 21(3l(l stronger than 85 percent and sodium nitrate to Well agitated sulfuric acid having a strength of between about 65 and-90 percent at a temperature between about 7'0 and 130 C.

8. The process of nitrating chlorobenzene to mononitrochlorobenzene which comprises the gradual and proportionate addition of sulfuric acid stronger than 85 percent and sodium nitrate to a well agitated mixture of chlorobenzene and sulfuric acid of about 0 65430 percent at a temperature between about 70 and 130 C.

9. In a V recess of manufacturing mononitrochlorob enzene, the step which comprises the gradual and proportionate addition of 1 sulfuric acid stronger than 85 percent, sodium nitrate and chlorobenzene to a well agitated mixture of sodium nitrate and sulfuric acid having a strength of to 90 percent and maintained at a. temperature between about 70 and 130 C.

-l0. in the process of manufacturing mono nitr u-hlorobeuzeue, the steps which cone prises adding the components, chlorohenzone, strong sulfuric acid and sodium niirate to diluted sulphuric acid at such a rate that the acidity of the sulphuric acid in the nitration in time is maintained at between about '70 and 90 percent strength 11. The process or manufacturing mononitrochlorobenzene which comprises the gradual and proportionate addition of about 1175 parts commercial pulverized sodium ni trate, about 1240 parts lnonochlorobenzene, and about 1600 parts sulfuric acid of about 93 percent strength to a well agitated mixture of about 200 parts monochlorobenzene and about 1000 parts of sulfuric acid of about 81 percent strength at a temperature of between about 100 and 130 C.

12. The rocess of manufacturing mono nitrochloro enzene which comprises the gradual and proportionate addition of about 1175 parts commercial pulverized sodium nitrate, about 1440 parts chlorobenzene and about 1600 parts sulfuric acid of about 93 percent strength to about 1000 parts sulfuric acid of about 81 percent strength which is well agitated and maintained at a temperature between about 100 and 130 C.

13. The process of manufacturing mononitrochlorobenzene which comprises the gradual and proportionate addition of about 1125 parts commercial pulverized sodium nitrate, about 1440 parts chlorobenzene and about 1600 parts 93 percent sulfuric acid to a well agitated mixture of about 1000 parts.

81 per cent sulfuric acid and 50 parts sodium nitrate at a temperature which is maintained at between about 100 and 130 C.

' JOHN W. LIVINGSTON.

LUCAS P. KYRIDES. 

